A variety of systems are used for automated inspection of objects such as semiconductor wafers, in order to detect defects, particles and/or patterns on the wafer surface as part of a quality assurance process in semiconductor manufacturing processes. It is a goal of current inspection systems to have high resolution and high contrast imaging in order to provide the reliability and accuracy demanded in sub-micron semiconductor manufacturing processes.
Various inspection systems have a masking module that controls the collection of beams that are scattered or reflected from the object. A masking module includes a predefined and limited number of apertures and the inspection system may select which of the apertures to use.
There is a growing need to evaluate existing masking modules and to evaluate future masking modules.